I just picked up a New Fender Vibrolux amp, it has the most incredible clean sound. I have a Rocktron Austin Gold pedal for a nice boost, with slight overdrive, which works out well for a little bite, but......... I still need to get that heavy Carcass meets Zakk Wylde sound. This amp is all tube but no master volume. Can anyone recommend a good pedal that will make this amp scream when I need it too?

Thanks in advance,
Howard Kolb
:)